--- loncom/Attic/lcuseradd 2000/10/29 22:38:21 1.4 +++ loncom/Attic/lcuseradd 2001/11/15 19:08:00 1.16 @@ -1,108 +1,352 @@ #!/usr/bin/perl + +# The Learning Online Network with CAPA +# +# lcuseradd - LON-CAPA setuid script to coordinate all actions +# with adding a user with filesystem privileges (e.g. author) # -# lcuseradd +# YEAR=2000 +# 10/27,10/29,10/30 Scott Harrison +# YEAR=2001 +# 10/21,11/13,11/15 Scott Harrison # -# Scott Harrison -# October 27, 2000 +# $Id: lcuseradd,v 1.16 2001/11/15 19:08:00 harris41 Exp $ +### + +############################################################################### +## ## +## ORGANIZATION OF THIS PERL SCRIPT ## +## ## +## 1. Description of script ## +## 2. Invoking script (standard input) ## +## 3. Example usage inside another piece of code ## +## 4. Description of functions ## +## 5. Exit codes ## +## 6. Initializations ## +## 7. Make sure this process is running from user=www ## +## 8. Start running script with www permissions ## +## 9. Handle case of another lcpasswd process (locking) ## +## 10. Error-check input, need 3 values (user name, password 1, password 2) ## +## 11. Start running script with root permissions ## +## 12. Add user and make www a member of the user-specific group ## +## 13. Set password ## +## 14. Make final modifications to the user directory ## +## 15. Exit script (unlock) ## +## ## +############################################################################### use strict; +# ------------------------------------------------------- Description of script +# # This script is a setuid script that should # be run by user 'www'. It creates a /home/USERNAME directory # as well as a /home/USERNAME/public_html directory. -# It adds user entries to -# /etc/passwd and /etc/groups. +# It adds a user to the unix system. # Passwords are set with lcpasswd. # www becomes a member of this user group. -# Standard input usage +# -------------- Invoking script (standard input versus command-line arguments) +# +# Standard input (STDIN) usage # First line is USERNAME # Second line is PASSWORD # Third line is PASSWORD - +# # Command-line arguments [USERNAME] [PASSWORD] [PASSWORD] # Yes, but be very careful here (don't pass shell commands) # and this is only supported to allow perl-system calls. +# +# Valid passwords must consist of the +# ascii characters within the inclusive +# range of 0x20 (32) to 0x7E (126). +# These characters are: +# SPACE and +# !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO +# PQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ +# +# Valid user names must consist of ascii +# characters that are alphabetical characters +# (A-Z,a-z), numeric (0-9), or the underscore +# mark (_). (Essentially, the perl regex \w). +# User names must begin with an alphabetical character +# (A-Z,a-z). +# ---------------------------------- Example usage inside another piece of code # Usage within code # -# $exitcode=system("/home/httpd/perl/lcuseradd","NAME","PASSWORD1","PASSWORD2")/256; +# $exitcode= +# system("/home/httpd/perl/lcuseradd","NAME","PASSWORD1","PASSWORD2")/256; # print "uh-oh" if $exitcode; +# ---------------------------------------------------- Description of functions +# enable_root_capability() : have setuid script run as root +# disable_root_capability() : have setuid script run as www +# try_to_lock() : make sure that another lcpasswd process isn't running + +# ------------------------------------------------------------------ Exit codes # These are the exit codes. +# ( (0,"ok"), +# (1,"User ID mismatch. This program must be run as user 'www'"), +# (2,"Error. This program needs 3 command-line arguments (username, ". +# "password 1, password 2)."), +# (3,"Error. Three lines should be entered into standard input."), +# (4,"Error. Too many other simultaneous password change requests being ". +# "made."), +# (5,"Error. User $username does not exist."), +# (6,"Error. Could not make www a member of the group \"$safeusername\"."), +# (7,"Error. Root was not successfully enabled.), +# (8,"Error. Cannot set password."), +# (9,"Error. The user name specified has invalid characters."), +# (10,"Error. A password entry had an invalid character."), +# (11,"Error. User already exists.), +# (12,"Error. Something went wrong with the addition of user ". +# "\"$safeusername\"."), +# (13,"Error. Password mismatch."), +# ------------------------------------------------------------- Initializations # Security -$ENV{'PATH'}=""; # Nullify path information. -$ENV{'BASH_ENV'}=""; # Nullify shell environment information. +$ENV{'PATH'}='/bin/:/usr/bin:/usr/local/sbin:/home/httpd/perl'; # Nullify path + # information +delete @ENV{qw(IFS CDPATH ENV BASH_ENV)}; # nullify potential taints -# Do not print error messages if there are command-line arguments -my $noprint=0; -if (@ARGV) { - $noprint=1; -} - -# Read in /etc/passwd, and make sure this process is running from user=www -open (IN, "; -close IN; -my $wwwid; -for my $l (@lines) { - chop $l; - my @F=split(/\:/,$l); - if ($F[0] eq 'www') {$wwwid=$F[2];} -} -if ($wwwid!=$<) { - print("User ID mismatch. This program must be run as user 'www'\n") unless $noprint; +# Do not print error messages. +my $noprint=1; + +# ----------------------------- Make sure this process is running from user=www +my $wwwid=getpwnam('www'); +&disable_root_capability; +if ($wwwid!=$>) { + print("User ID mismatch. This program must be run as user 'www'\n") + unless $noprint; exit 1; } + +# ----------------------------------- Start running script with www permissions &disable_root_capability; -# Handle case of another lcpasswd process +# --------------------------- Handle case of another lcpasswd process (locking) unless (&try_to_lock("/tmp/lock_lcpasswd")) { - print "Error. Too many other simultaneous password change requests being made.\n" unless $noprint; + print "Error. Too many other simultaneous password change requests being ". + "made.\n" unless $noprint; exit 4; } -# Gather input. Should be 3 values (user name, password 1, password 2). +# ------- Error-check input, need 3 values (user name, password 1, password 2). my @input; -if (@ARGV==1) { +if (@ARGV==3) { @input=@ARGV; } elsif (@ARGV) { - print("Error. This program needs 3 command-line arguments (username, password 1, password 2).\n") unless $noprint; + print("Error. This program needs 3 command-line arguments (username, ". + "password 1, password 2).\n") unless $noprint; unlink('/tmp/lock_lcpasswd'); exit 2; } else { @input=<>; - if (@input!=1) { - print("Error. Three lines should be entered into standard input.\n") unless $noprint; + if (@input!=3) { + print("Error. Three lines should be entered into standard input.\n") + unless $noprint; unlink('/tmp/lock_lcpasswd'); exit 3; } - map {chop} @input; + map {chomp} @input; } my ($username,$password1,$password2)=@input; $username=~/^(\w+)$/; my $safeusername=$1; -$password1=~/^(\w+)$/; -my $password1=$1; -$password2=~/^(\w+)$/; -my $safepassword2=$1; +if (($username ne $safeusername) or ($safeusername!~/^[A-Za-z]/)) { + print "Error. The user name specified has invalid characters.\n" + unless $noprint; + unlink('/tmp/lock_lcpasswd'); + exit 9; +} +my $pbad=0; +map {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}} (split(//,$password1)); +map {if ((ord($_)<32)||(ord($_)>126)){$pbad=1;}} (split(//,$password2)); +if ($pbad) { + print "Error. A password entry had an invalid character.\n"; + unlink('/tmp/lock_lcpasswd'); + exit 10; +} -&enable_root_capability; +# -- Only add user if we can create a brand new home directory (/home/username) +if (-e "/home/$safeusername") { + print "Error. User already exists.\n" unless $noprint; + unlink('/tmp/lock_lcpasswd'); + exit 11; +} -# Add user entry to /etc/passwd and /etc/groups in such -# a way that www is a member of the user-specific group +# -- Only add user if the two password arguments match. +if ($password1 ne $password2) { + print "Error. Password mismatch.\n" unless $noprint; + unlink('/tmp/lock_lcpasswd'); + exit 13; +} -# This command 'should' make the user be a member of just +# ---------------------------------- Start running script with root permissions +&enable_root_capability; + +# ------------------- Add user and make www a member of the user-specific group +# -- Add user +if (system('/usr/sbin/useradd','-c','LON-CAPA user',$safeusername)) { + print "Error. Something went wrong with the addition of user ". + "\"$safeusername\".\n" unless $noprint; + unlink('/tmp/lock_lcpasswd'); + exit 12; +} -if (system('/usr/sbin/useradd','-c','LON-CAPA user','-G','www',$safeusername)) { - print "Error. Something went wrong with the addition of user \"$safeusername\".\n"; +# Make www a member of that user group. +if (system('/usr/sbin/usermod','-G',$safeusername,'www')) { + print "Error. Could not make www a member of the group ". + "\"$safeusername\".\n" unless $noprint; unlink('/tmp/lock_lcpasswd'); - exit 5; + exit 6; } +# ---------------------------------------------------------------- Set password # Set password with lcpasswd (which creates smbpasswd entry). +unlink('/tmp/lock_lcpasswd'); +&disable_root_capability; +($>,$<)=($wwwid,$wwwid); +open OUT,"|/home/httpd/perl/lcpasswd"; +print OUT $safeusername; +print OUT "\n"; +print OUT $password1; +print OUT "\n"; +print OUT $password1; +print OUT "\n"; +close OUT; +($>,$<)=($wwwid,0); +if ($?) { + exit 8; +} +&enable_root_capability; + +# ------------------------------ Make final modifications to the user directory +# -- Add a public_html file with a stand-in index.html file + +# system('/bin/chmod','-R','0660',"/home/$safeusername"); +system('/bin/chmod','0710',"/home/$safeusername"); +mkdir "/home/$safeusername/public_html",2760; +open OUT,">/home/$safeusername/public_html/index.html"; +print OUT< + +$safeusername + + +

$safeusername

+

+Learning Online Network +

+

+This area provides for: +

+ + + +END +close OUT; +system('/bin/chown','-R',"$safeusername:$safeusername","/home/$safeusername"); + +# -------------------------------------------------------- Exit script +&disable_root_capability; +exit 0; + +# ---------------------------------------------- Have setuid script run as root +sub enable_root_capability { + if ($wwwid==$>) { + ($<,$>)=($>,$<); + ($(,$))=($),$(); + } + else { + # root capability is already enabled + } + return $>; +} + +# ----------------------------------------------- Have setuid script run as www +sub disable_root_capability { + if ($wwwid==$<) { + ($<,$>)=($>,$<); + ($(,$))=($),$(); + } + else { + # root capability is already disabled + } +} + +# ----------------------- Make sure that another lcpasswd process isn't running +sub try_to_lock { + my ($lockfile)=@_; + my $currentpid; + my $lastpid; + # Do not manipulate lock file as root + if ($>==0) { + return 0; + } + # Try to generate lock file. + # Wait 3 seconds. If same process id is in + # lock file, then assume lock file is stale, and + # go ahead. If process id's fluctuate, try + # for a maximum of 10 times. + for (0..10) { + if (-e $lockfile) { + open(LOCK,"<$lockfile"); + $currentpid=; + close LOCK; + if ($currentpid==$lastpid) { + last; + } + sleep 3; + $lastpid=$currentpid; + } + else { + last; + } + if ($_==10) { + return 0; + } + } + open(LOCK,">$lockfile"); + print LOCK $$; + close LOCK; + return 1; +} + +=head1 NAME + +lcuseradd - LON-CAPA setuid script to coordinate all actions + with adding a user with filesystem privileges (e.g. author) + +=head1 DESCRIPTION + +lcuseradd - LON-CAPA setuid script to coordinate all actions + with adding a user with filesystem privileges (e.g. author) + +=head1 README + +lcuseradd - LON-CAPA setuid script to coordinate all actions + with adding a user with filesystem privileges (e.g. author) + +=head1 PREREQUISITES + +=head1 COREQUISITES + +=pod OSNAMES + +linux + +=pod SCRIPT CATEGORIES + +LONCAPA/Administrative + +=cut